The controller is the part of an LED system that fails on site, and the part most often bought last. A screen with the right pitch and the wrong processor looks worse than a coarser screen running properly.
Start with pixel capacity, not price
Controllers are specified in pixels they can drive, not in square metres. Calculate the native resolution of the largest wall you will build, then add headroom for a second wall or a wider format.
Native resolution is physical size divided by pitch — see how to calculate LED screen resolution. A 6 × 3 m P3.91 wall is about 1536 × 768, or 1.18 million pixels. A 12 × 6 m wall at the same pitch is 4.7 million, which is a completely different controller class.
Frame rate and refresh are different things
- Refresh rate (Hz) is how fast the LED panel redraws. It needs to be 3,840 Hz or higher for camera work. This is a panel and driver property, not a controller property — but a weak controller can force it down.
- Frame rate is how many frames per second the processor sends. 60 Hz is the baseline for smooth motion; 50 Hz matters in 50 Hz regions for broadcast.
A controller that cannot sustain 60 Hz at native resolution will drop frames or scale the image down, and it will do it in front of the client.
The features that matter on a rental
- Input flexibility. At minimum HDMI and SDI; DisplayPort and 12G-SDI if you work broadcast or high frame rate.
- Scaling quality. Content rarely arrives at native resolution. A good scaler preserves text; a cheap one softens it.
- Genlock / sync. Needed when the screen appears on camera alongside other displays, or when two walls must stay in sync.
- Backup and hot spare. Can a second processor take over without a rebuild? On a live show this is worth more than any other feature.
- Presets. Recall a saved configuration for each standard wall size your fleet builds.
- Front-panel and remote control. You want to change a preset without opening a laptop in a dark wingspace.
Processing vs sending cards
The processor outputs to sending cards, which distribute to the cabinets. Capacity is limited by both. Check the total pixel count the sending card chain supports, not just the processor’s own figure — the bottleneck is often the sending side.
Also confirm the cabinet wiring standard: some cabinets carry data over a hub board, some over individual module cables. That affects how a controller maps to the wall and how a spare cabinet is configured.
What to test before you buy
- Drive your largest real wall from your own media server, at native resolution, for 30 minutes.
- Send a 1-pixel checkerboard: it exposes scaling and cabling faults immediately.
- Send 5 percent grey and look for banding.
- Pull the main processor out and confirm the backup takes over.
- Film the wall with a phone at 1/1000 shutter to confirm no scan lines.
Common mistakes
- Sizing for the wall you have today. Fleets grow; buy one class above your current maximum.
- Ignoring the media server. The controller is not the playback device. Confirm the server can output the resolution and frame rate you need.
- One processor for everything. A single unit is a single point of failure on a paid show.
- No spare sending card. They fail more often than processors and cost a fraction as much.
- Skipping the preset setup. A wall rebuilt from memory under time pressure is where errors happen.
Frequently asked questions
Can one controller run two different walls?
Usually yes, as separate outputs, if the total pixel count fits. Whether you want that on a live show is a reliability question, not a technical one.
Do I need 4K?
Only if your walls reach 4K natively, which for most rental stock means a wall larger than 10 m at fine pitch. Otherwise 1080p processing at high frame rate is the better spend.
Does the controller affect power consumption?
Marginally. It adds a small load, but it is not a factor in cabinet power calculations.
Can I use one brand of controller with another brand of cabinet?
Usually yes, because the interface is standard. Confirm the receiving card type and the cabinet wiring before assuming compatibility.
Tell us the largest wall you build
Send the maximum width, height and pitch in your fleet and we will tell you the pixel capacity and frame rate you need to specify. Start from the rental LED range or message us through the contact page. If you are still choosing the screen itself, read the rental LED buying guide first.